More information on how this exercise can be used in your classes

This virtual laboratory exercise can be used as a supplement to your existing curriculum or as a pre-lab to experiments related to those illustrated in the lab. There are quiz questions embedded in the laboratory. These quizzes, designed to further the user's understanding, can be used several ways. Your students may choose to submit answers to the quizzes, or they may skip the questions. If you, the teacher, would like assurance that the quiz questions have been answered, you may ask your students to print out their responses.

The laboratory focuses on the production of transgenic flies that contain the period promoter adjacent to the luciferase reporter gene. However, the techniques illustrated in this virtual laboratory can be used to insert many different types of DNA constructs. You may choose to expand the laboratory by having your students simulate the production of other types of transgenic flies. You may investigate other genes involved in circadian rhythms, such as the timeless gene for which tim-luc constructs have been made (Stanewsky et al. 1998). Students may compare the tim-luc data with that of the per-luc data. Teachers can also adapt this laboratory to study genes important in a wide range of biological functions.

Researchers regularly use molecular biology sequence databases for many purposes, including the design of constructs used in creating transgenic organisms. Embedded in the laboratory (Part 1: Prepare DNA) is a short tutorial on the use of a few key resources available through the National Center for Biotechnology Information (NCBI) at the National Institute of Health (NIH). Students use these resources within the context of this virtual lab to confirm that the sequence in the construct they are using is indeed from the per promoter. You may want to expand your students' explorations of molecular biology resources by following links to NCBI education sites. In addition to learning about available NCBI resources, your students can learn about the per gene in humans and relationships to human circadian biology disorders (see http://www.ncbi.nlm.nih.gov/Class/MLACourse/Modules/cover_circadian_exercises.html).

This exercise guides students through the development and analysis of hypothesis-driven research problems. Students select and test a hypothesis by performing virtual experiments and analyzing data. Data tables are completed and can be printed and turned in to an instructor. Following the analysis of the data, students are asked questions about their results and asked to evaluate their hypothesis. The exercises emphasize the importance of analysis and interpretation, even when the hypothesis turns out to be incorrect.

The laboratory may also be a starting point to discuss issues related to biotechnology. What regulations are researchers required to follow when producing genetically engineered organisms? Should there be fewer or more regulations? What might happen if one of the glowing flies was accidentally released into the wild?

Especially when the virtual lab is used as an exercise that precedes actual laboratory experiments, different steps can be discussed in more detail. For example, in Part 5, when the flies are being sorted, a few flies wake up and fly away from the microscope stage. What could be done to keep the flies anesthetized for a longer period? A different anesthetic, such as ether, could be used. Or, the stage could be re-designed so that CO₂ flows in a compartment below the sorting stage, keeping the flies anesthetized.